Systems and methods for injecting flowable materials into bones

ABSTRACT

A device is introduced into the vertebral body through a percutaneous access path. The device is manipulated to modify the cancellous bone volume for introduction of bone filling material. Bone filling material is introduced into the cancellous bone volume modified by the device along the percutaneous path. Discharge of the bone filling material is directed into the cancellous bone volume through an opening that is oriented at an angle relative to the axis of the access path.

RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.10/630,519, filed Jul. 30, 2003, and entitled “Systems and Methods forInjecting Flowable Materials Into Bone,” which is a divisional of U.S.patent application Ser. No. 09/893,298, filed Jun. 27, 2001 (now U.S.Pat. No. 6,645,213), which claims the benefit of provisional applicationSer. No. 60/214,666 filed 27 Jun. 2000, and which is also acontinuation-in-part of U.S. patent application Ser. No. 09/496,987,filed Feb. 2, 2000 (now U.S. Pat. No. 6,719,761), which is a divisionalof U.S. patent application Ser. No. 08/910,809, filed Aug. 13, 1997 (nowU.S. Pat. No. 6,048,346), each of which is incorporated herein byreference.

FIELD OF THE INVENTION

The invention relates to the treatment of bone conditions in humans andother animals.

BACKGROUND OF THE INVENTION

Several companies offer mechanical bone cement injection devices. Thesedevices are similar to a household caulking gun. Typically, theinjection device has a pistol-shaped body, which supports a cartridgecontaining bone cement. The cement is typically in two-parts and must bemixed in a mixer and transferred into the cartridge for injection.

Just after mixing, and prior to curing, the cement is in a flowing,viscous liquid state, similar to a syrup or watery pancake batter inconsistency. The injection device has a ram, which is actuated by amanually movable trigger or screwing mechanism for pushing the viscousbone cement out the front of the cartridge through a suitable nozzle andinto the interior of a bone targeted for treatment.

Once injected into the targeted bone, the cement undergoes a curingcycle of perhaps 6 to 8 minutes. While curing, the cement passes from aviscous liquid to a putty-like consistency and finally to a hard rigidblock.

SUMMARY OF THE INVENTION

The invention provides, in its various aspects, greater control over theplacement of cement and other flowable liquids into bone.

One aspect of the invention provides a method that comprises selecting avertebral body for treatment having a cortical wall enclosing acancellous bone volume. The method establishes a percutaneous accesshaving a longitudinal axis leading to the cancellous bone volume, andintroduces a device into the vertebral body through the percutaneousaccess path. The method manipulates the device to modify the cancellousbone volume for introduction of bone filling material. The methodintroduces bone filling material into the cancellous bone volumemodified by the device. The introduction includes introducing bonefilling material along the percutaneous path and directing discharge ofthe bone filling material into the cancellous bone volume through anopening that is oriented at an angle relative to the longitudinal axis.

The percutaneous path can comprise, e.g., a transpedicular path or apostero-lateral path. The path can comprise, e.g., a cannula.

Modifying the cancellous bone volume can include, e.g., contactingcancellous bone with the device by, e.g., expanding the device and/orinflating the device for contact with cancellous bone. Modifying thecancellous bone volume can also include, e.g., manipulating the deviceto create a cavity in cancellous bone, and/or manipulating the device tomove fractured cortical bone.

Introducing the bone filling material into the cancellous bone volumecan include, e.g., coupling a delivery tube to an injector of bonefilling material, advancing the delivery tube along the percutaneouspath, and operating the injector to convey bone filling material alongthe percutanous path through the delivery tube. The delivery tube caninclude, e.g., a threaded coupling for coupling the delivery tube to theinjector.

Features and advantages of the inventions are set forth in the followingDescription and Drawings, as well as in the appended Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a system for treating bone, which includes ainjector nozzle assembly embodying features of the invention;

FIG. 2 is an enlarged side view of the dispensing end of one embodimentof the injector nozzle assembly shown in FIG. 1, in which the dispensingend is prebent in a desired geometry to facilitate its deployment;

FIG. 3A is an enlarged side view of the dispensing end of anotherembodiment of the injector nozzle assembly shown in FIG. 1, in which thedispensing end is steerable to facilitate its deployment within bone;

FIG. 3B is an enlarged side view of an alternative embodiment of asteerable dispensing end for the injector nozzle assembly shown in FIG.1;

FIG. 4 is an enlarged end view of the dispensing end of one embodimentof the injector nozzle assembly shown in FIG. 1, which carries a loopformed for cutting cement free from the dispensing end;

FIG. 5 is an enlarged end view of the dispensing end shown in FIG. 4,illustrating the rotation of the cement cutting loop to cut free anejected cement bolus;

FIG. 6 is an enlarged end view of the dispensing end of one embodimentof the injector nozzle assembly shown in FIG. 1, which carries twocriss-crossing loops formed for cutting cement free from the dispensingend;

FIG. 7 is an enlarged end view of the dispensing end of one-embodimentof the injector nozzle assembly shown in FIG. 1, in which the dispensingend is steerable and also carries a loop formed for cutting cement freefrom the dispensing end;

FIG. 8 is an enlarged end view of the dispensing end of anotherembodiment of the injector nozzle assembly shown in FIG. 1, in which thedispensing end is steerable and also carries two loops formed forcutting cement free from the dispensing end;

FIG. 9 is an enlarged end view of the dispensing end of one embodimentof the injector nozzle assembly shown in FIG. 1, which carries a prebentstylet, which is shown in a retracted and straightened condition priorto use;

FIG. 10 is an enlarged end view of the dispensing end shown in FIG. 9,illustrating the rotation of the prebent stylet after advancement to cutfree an ejected cement bolus;

FIG. 11 is a section view of the prebent stylet taken generally alongline 11-11 in FIG. 9, showing a mating tab and keyway that preventsrotation of the stylet out of a desired orientation during use;

FIG. 12 is a side view of one embodiment of the injector nozzle assemblyshown in FIG. 1, which includes a side port for dispensing cement;

FIG. 13 is an enlarged end view of the injector nozzle assembly shown inFIG. 12, illustrating the rotation of the dispensing end to cut free anejected cement bolus from the side dispensing port;

FIG. 14 is an enlarged side section view of an injector nozzle assemblywhich includes a rotating fitting that allows the injector tube to berotated independent of the cement injecting tool;

FIG. 15 is a side view of an injector nozzle assembly with a rotatingfitting like that shown in FIG. 14, which includes index markers forascertaining the orientation of the dispensing end and the extent towhich the dispensing end is rotated, without need of directvisualization;

FIG. 16 is a coronal view of a vertebral body, partially cut away and insection, illustrating the deployment, by postero-lateral access, of anexpandable body to compress cancellous bone and form an interior cavity;

FIG. 17 is a coronal view of the vertebral body shown in FIG. 16,illustrating the deployment of the injector nozzle assembly shown inFIG. 1 by postero-lateral access;

FIG. 18 is a lateral view of a vertebral body, partially cut away and insection, illustrating the deployment of the injector nozzle assemblyshown in FIG. 1 by transpedicular access into a cavity previously formedby an expanded body;

FIGS. 19A, 19B, and 19C are side views of an injector nozzle assembly,which also includes index markers for ascertaining the extent to whichthe dispensing end is extended into the targeted treatment site, withoutthe need for direct visualization;

FIG. 20 is a side view of a system which includes an injector nozzleassembly coupled to a source of cooling fluid to mediate the increase intemperature of curing cement dispensed by the assembly;

FIG. 21 is a somewhat diagrammatic side section view of the injectornozzle assembly shown in FIG. 20;

FIG. 22 is an end view of the injector nozzle assembly shown in FIG. 20;

FIG. 23 is a side view, with portions broken away and in section, of analternative injector nozzle assembly providing variable rates ofdelivery;

FIG. 24 is a top view, with portions broken away and in section, of theinjector nozzle assembly shown in FIG. 23;

FIG. 25 is an exploded view, with portions broken away and in section,of the injector nozzle assembly shown in FIG. 23;

FIG. 26 is a side view, with portions broken away and in section, of theinjector nozzle assembly shown in FIG. 23, being operated to provide afast rate, high volume delivery of flowable material; and

FIG. 27 is a side view, with portions broken away and in section, of theinjector nozzle assembly shown in FIG. 23, being operated to provide aslower, metered delivery rate of flowable material.

The invention may be embodied in several forms without departing fromits spirit or essential characteristics. The scope of the invention isdefined in the appended claims, rather than in the specific descriptionpreceding them. All embodiments that fall within the meaning and rangeof equivalency of the claims are therefore intended to be embraced bythe claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows an injector nozzle assembly 10 for conveying a flowablematerial into bone. The assembly 10 is capable of carrying diverse typesof flowable materials, e.g., bone cement or a suspension of one or moretherapeutic substances, or both at the same time. The assembly 10 canlikewise be used for diverse therapeutic purposes, as well, e.g., totreat a diseased bone, or to prevent or treat fracture or collapse of abone, or both at the same time.

The illustrated embodiment shows the injector nozzle assembly 10 as partof a system 11, which injects cement for treating bone fracture orcollapse, which is a purpose for which the assembly 10 is particularlywell adapted. It should be appreciated, however, that the nozzleassembly 10 is not limited to use in the treatment of bone fractures orcollapse.

FIG. 1 shows the system 11 to include a tool 12 that forms acement-receiving cavity in cancellous bone and a tool 14, to which theassembly 10 is releasably attached to convey cement into the formedcancellous bone cavity.

In FIG. 1, the first tool 12 includes a catheter tube 16 having a distalend 18, which carries an expandable body 20. FIG. 1 shows the body 20 ina collapsed geometry, which permits the physician to insert the body 20into the interior volume of a targeted bone. Once inserted into bone,the physician can convey fluid to expand the body 20, as shown inphantom lines in FIG. 1.

As will be described in greater detail later, expansion of the body 20creates a cavity in cancellous bone. The use of expandable bodies totreat bones in this fashion is disclosed in U.S. Pat. Nos. 4,969,888 and5,108,404, which are incorporated herein by reference.

The nozzle assembly 10 is deployed into the formed cavity to dispensebone cement, as will also be described in greater detail later. Thecement cures and hardens to provide renewed interior structural supportfor cortical bone surrounding the cancellous bone.

Further details of the injection nozzle assembly 10 will now bedescribed.

I. The Injection Nozzle Assembly

The injection nozzle assembly 10 is intended to be component that can beremovably connected to a conventional injection tool 14, e.g., by athreaded connector 36 (see FIG. 2). As FIG. 1 shows, the tool 14comprises a pistol-shaped grip, which will be referred to as a gun 22.The gun 22 includes an end fitment 24, to which a cartridge 26 isremovably attached, for example, by threaded screw engagement (notshown). The cartridge 26 includes an interior, movable piston 28.

As FIG. 2 best shows, the nozzle assembly 10 comprises an injection tube30. The injection tube is releasably coupled to the front end of thecartridge 26 by the threaded connector 36, which mates with a screwconnector 37 on the cartridge.

The injection tube 30 includes a center lumen 32. The nozzle assembly 10also includes a distal dispensing end 34, through which the center lumen32 extends.

In use (see FIG. 1), the cartridge 26 contains bone cement 38. Thecartridge 26 can be loaded with bone cement 38 in various way. Forexample, bone cement 38 is typically mixed in an external mixing device(not shown) from two components. Upon mixing, the two components beginto cure from a low viscosity, relatively free flowing liquid, like athin pancake batter, to a substantially less flowable, putty likecharacter. Eventually the cement 38 hardens to a rigid state within thetargeted bone cavity formed by the expandable body 20.

Because of the increasing viscosity (lessening flow) of the bone cement38, it should preferably be injected within a few minutes followingmixing. For this purpose, a ram rod 40 extends within the gun 22. Therod 40 carries a ram disk 44. The rod 40 is coupled to a finger trigger42.

When the physician pulls the trigger 42 rearward (as arrow 43 shows inFIG. 1), the rod 40 advances the ram disk 44 into contact with thecartridge piston 28. Advancement of the cartridge piston 28, in turn,pushes the bone cement 38 through the screw connector 37 into the lumen32 of the injection tube 30 and out through the dispensing end 34, asFIG. 1 shows.

Details of the gun 22 can be conventional and are not essential to theinvention. The gun 22 can comprise a cement gun made, for example, byStryker Corporation (Kalamazoo, Mich.). This particular gun has amanually operated trigger with a mechanical advantage of about 9 to 1.Other injection guns may be used, having more or less mechanicaladvantage. Non-manually operated injection guns can also be used.

The nozzle assembly 10 can be constructed in various ways. For example,the injector tube 30, including its dispensing end 34, can be made of aplastic material, such as polyethylene or other suitable polymer. Thediameter and length of the nozzle assembly 10 will vary according to thenature of the procedure. For example, for delivering cement in the hipregion, the nozzle assembly 10 can be about 10 to 30 cm long with anouter diameter of about 4 to 12 mm. For delivering cement to a vertebralbody, the nozzle assembly 10 can be about 18 to 30 cm long with an outerdiameter of about 3 to 8 mm in diameter.

A. Deflecting the Dispensing End

As FIGS. 1 and 2 show, the dispensing end 34 of the nozzle assembly 10is either deflected or is otherwise capable of being deflected outsidethe main axis 46 of the tube 30. The deflection defines a radius ofcurvature, which aids in the deployment of the dispensing end 34 withinthe targeted region. The advantages of the deflected dispensing end 34will be discussed in greater detail later, as illustrated in the contextof its deployment in a vertebral body.

The deflection of the distal tube end 36 can be accomplished in variousways, which the following description exemplifies.

1. Fixed Deflection

In the embodiment shown in FIG. 2, the dispensing end 34 is normallybiased into a prescribed deflected condition. The bias can be thermallyset, using, for example, polyurethane or nylon material for the tube.Alternatively (as FIG. 2 shows), the dispensing end 34 can carry alength of prebent memory wire material 48, made from, e.g., anickel-titanium alloy, which biases the dispensing end 34 toward thedesired deflected geometry. The angle of the deflection can vary,according to the geometry at the intended treatment site.

As will be described in greater detail later, the bias is overcome bypassage of the dispensing end 34 through a guide sheath, whichtemporarily straightens the dispensing end 34 during its deployment inthe intended treatment site. When free of the confines of the guidesheath, the bias returns the dispensing end 34 to its preestablisheddeflected condition.

2. Adjustable Deflection

In an alternative embodiment, as FIG. 3A shows, the injection tube 30carries steering wires 50 and 52. The steering wires 50 and 52 extendthrough side lumens, respectively 50A and 52A in the tube 30 and arecoupled to the dispensing end 34.

In FIG. 3A, two steering wires 50 and 52 are shown for the purpose ofillustration, but it should be realized that more or fewer steeringwires may be used. The steering wires 50 and 52 are coupled to asteering mechanism 54 located on the proximal end of the tube 30 nearthe gun cartridge 26, for manipulation by the physician. In FIG. 3A, thesteering mechanism 54 comprises a rotatable wheel 56 with a controllever 55, to which the steering wires 50 and 52 are coupled. Other typesof steering mechanisms 54, such as pull tabs or linear actuators, can beused.

Counterclockwise rotation of the wheel 56 (arrow direction A) pulls onthe first steering wire 50, deflecting the dispensing end 34 upward(phantom line position 34A in FIG. 3A). Clockwise rotation of the wheel56 (arrow direction B) pulls on the second steering wire 52, deflectingthe dispensing end 34 downward (phantom line position 34B in FIG. 3A).Multi-directional steering is thereby achieved.

In an alternative embodiment (see FIG. 3B), position of the controllever 55 corresponds with the angular orientation of the dispensing end34. When the control lever 55 is located in the center position C, thedispensing end 34 is in a straightened condition C′. When the controllever 55 is moved down or clockwise (for example, to phantom lineposition D) the dispensing end 34 is likewise moved to phantom lineposition D′, and the rotation angle Al between position C and Dgenerally corresponds with the deflection angle A1′ between position C′and D′. Likewise, when the control lever 55 is moved up orcounterclockwise (for example, to phantom line position E) thedispensing end 34 is likewise moved to phantom line position E′, and therotation angle A2 between position C and E generally corresponds withthe deflection angle A2′ between position C′ and E′.

B. Cutting the Expelled Cement Bolus

1. Cutting Wires

As FIG. 4 shows, one embodiment of the nozzle assembly 10 includes alength of wire 100 carried by the dispensing end 34. The wire 100extends across the central opening 32, forming a loop 102 for cuttingloose the cement bolus 62 expelled through the lumen 32.

As FIGS. 4 and 5 show, rotation of the injection tube 30 (as arrow 60 inFIG. 5 shows) rotates the dispensing end 34 and, with it, the loop 102.The loop 102 rotates within the expelled bolus 62 of cement adjacent theterminal end of the lumen 32. Rotation of the loop 102 through 180° cutsloose the expelled cement bolus 62 from the unexpelled cement mass 64,which resides within the dispensing end 34. The loop 102, integrallycarried by the dispensing end 34, creates a consistent and clean breakbetween the expelled bolus 62 and the unexpelled mass 64.

In the embodiment shown in FIG. 6, the nozzle assembly 10 includes twolengths of wire 126 and 128 carried by the dispensing end 34. The wires126 and 128 cross over the center lumen 32, forming two cement cuttingloops 130 and 132 in the path of cement expelled by the lumen 32.Rotation of the dispensing end 34 through 90° passes the two loops 64and 66 through the cement bolus 62, severing the cement bolus 62 fromthe cement mass residing in the dispensing end 34, in the manner shownin FIG. 5.

As FIG. 6 shows, the dispensing end 34 of the injection tube 30 shown inFIGS. 4 to 6 can, if desired, be preformed with a normal deflection, aspreviously described, to offset the dispensing end 34 with respect tothe axis 46 of the injection tube 30. The tube 30 can also carrysteering wires 50 and 52, as shown in FIG. 3, to steer the dispensingend 34.

Alternatively, the steering and cement cutting elements can be combined.For example, in the embodiment shown in FIG. 7, the nozzle assembly 10includes a length of wire 134, which is threaded through side lumens136A and 136B, which extend through the tube 30 (in the manner shown inFIG. 3). The wire 134 forms an exterior loop 58 at the tip of thedispensing end 34. In the illustrated and preferred embodiment, the sidelumens 136A and 136B are generally diametrically spaced with respect tothe center lumen 32, so that the exterior loop 58 extends across thecenter lumen 32, generally bisecting it. The exterior loop 58 serves asa cement cutting tool, as previously described.

In FIG. 7, the wire 134 is fixed to the tip of the dispensing end 34, sothat pulling on either leg of the wire 134 will bend the dispensing end134. The legs of the threaded wire 134 thereby serve as the first andsecond steering wires 50 and 52, which deflect the dispensing end 34 inthe manner previously described and shown in FIG. 3.

FIG. 8 shows another alternative embodiment, in which two lengths ofwires 138 and 140 are threaded through multiple pairs of side lumens142A, 142B, 144A, and 144B, which extend through the tube 30. The wires138 and 140 forming circumferentially spaced, multiple steering wires50, 51, 52, and 53. The wires 138 and 140 also cross over the centerlumen 32, forming two loops 64 and 66 across the dispensing end 34. Thewires 138 and 140 are fixed by adhesive or other suitable manner to thetip of the dispensing end, forming multiple steering wire legs 50, 51,52, 53. The fixed legs 50, 51, 52, and 53 provide multi-planar steering.The two loops 64 and 66 also serve as cement cutters.

FIGS. 9 to 11 show an alternative embodiment of a nozzle assembly 10,which includes a bent stylet 200 to cut loose an expelled cement bolus62. The stylet 200 is slidably carried by an interior lumen 202 in theinjection tube 30. As FIG. 11 best shows, a locating tab 206 on thestylet 200 mates with a groove or keyway 208 in the lumen 202, toprevent rotation of the stylet 200 in the lumen 202. A suitablepush-pull mechanism (not shown) is accessible at the proximal end of theinjection tube 30 to affect advancement and retraction of the stylet 200in the lumen 202.

As FIG. 10 shows, the distal end 204 of the stylet 200 is preformed withan angle bend. When located in the lumen 202 (as FIG. 9 shows), thedistal end 204 is retained in a straightened condition. When advancedfree of the lumen 202, the distal end 204 assumes the preformed, bentconfiguration. The locating tab 206 and mating keyway 208 orient thestylet 200, so that, when moved free of the lumen 202, the distal end204 bends toward and over the central opening 32 of the tube 32, as FIG.10 shows. The distal end 204 preferably extends at least half way ormore across the central opening 32 of the tube 30.

In use, while the distal stylet end 204 is withdrawn in the lumen 202,the cement bolus 62 is expressed from the central opening 32 of thedispensing end 34(as FIG. 9 shows). When cement injection is completed,the physician slides the distal stylet end 204 forward from the lumen202. The stylet end 204, freed from the lumen 202, bends over thecentral opening 32 into the cement bolus 62. Rotation of the dispensingend 34 through 360° (arrow 209 in FIG. 10) passes the distal stylet end204 through the cement bolus 62, severing the bolus 62 from the cementmass in the dispensing end 34. The physician pulls on the stylet 200 toreturn the distal stylet end 204 to the lumen 202.

2. Side Injection Port

FIGS. 12 and 13 show another alternative embodiment of a nozzle assembly10 which, upon rotation, cuts loose an expelled cement bolus 62.

In this embodiment, the nozzle assembly 10 includes an injection tube 30like that shown in FIG. 2. The tube 30 includes a threaded connector 36,which screws onto the connector 37 of the cement gun cartridge 26. Thetube 30 includes a center lumen 32 to transport cement from thecartridge 26 to a distal dispensing end 34.

Unlike the embodiment shown in FIG. 2, the center lumen 32 does notextend axially through the tip of the distal dispensing end 34. Instead,in FIGS. 12 and 13, the tip of the dispensing end 34 is closed andincludes at least one dispensing port 180 extending at an angle from thecentral lumen 32. The port 180 opens on a side of the dispensing end 34.

As FIG. 13 shows, the cement bolus 62 is expressed through the sidedispensing port 180, and not through the distal tip of the dispensingend 34. As FIG. 13 shows, rotation of the dispensing end 34 (indicatedby arrow 182) moves the dispensing port 180 along an arc transversely ofand away from the cement bolus 62. The transverse movement of the sidedispensing port 180 away from the bolus 32 severs the bolus 32 from thecement mass residing in the center lumen 32.

As FIG. 12 shows, the dispensing end 34 of the injection tube 30 can, ifdesired, be preformed with a normal deflection, as previously described,to offset the dispensing end 34 with respect to the axis 46 of theinjection tube 30. The tube 30 can also carry steering wires 50 and 52,as shown in FIG. 3, to steer the dispensing end 34.

3. Rotating Fitting

As FIG. 14 shows, the threaded connector 36, which releasably couplesthe injection tube 30 to the screw connector 37 on the front end of thecartridge 26 of the cement gun 22, can include a fitting 104 thatpermits rotation of the injection tube 30 relative to the connector 36and the gun 22.

Various constructions for the rotating fitting 104 are possible. In theillustrated embodiment, the rotating fitting 104 includes an adaptor 108carried for rotation within the connector 36. The proximal end 110 ofthe injector tube 30 is secured to the adaptor 108 for common rotation.A retaining ring 112 outside the connector 36 surrounds tube 30,allowing its rotation but otherwise restraining rearward axial movement.An o-ring 114 is contained between the adaptor 108 and the end wall ofthe connector 36. The o-ring 114 restrains forward axial movement of thetube 30, while also preventing leakage of cement.

The rotating fitting 104 permits the physician to rotate the injectiontube 30 with one hand, and thereby rotate the nozzle 34 (as arrows 106show in FIG. 14), while holding the gun 22 stationary in another hand.As FIG. 14 shows, the injection tube 30 can carry a hub or grip 115 tofacilitate rotation.

The rotating fitting 104 simplifies handling and manipulation of thecement injection tool 14 during rotation of the injection tube 30. Thephysician is able to rotate the injection tube 30, causing the one ormore cement cutting loops carried by the rotating dispensing end 34 tocut loose an expelled cement bolus 62 (as shown in FIGS. 4 and 5, 9 and10, and 12 and 13), without rotating the gun 22 itself. When combinedwith a deflected dispensing end 34, rotation of the tube 30 furtherhelps locate the dispensing end 34 in the desired position, againwithout the need to rotate the gun 22.

As FIG. 15 shows, the rotating fitting 104 can include indicia to gaugeorientation or rotation of the injection tube 30. In the illustratedembodiment, the indicia includes an index mark 210 scribed on theconnector 36, which aligns with an index mark 212 scribed on theproximal end of the injection tube 30. Alignment of the marks 210 and212 places the dispensing end 34 in a particular, preestablishedorientation.

For example, when the dispensing end 34 is normally biased in adeflected condition, as FIG. 15 shows, alignment of the marks 210 and212 can designate that the deflection is to the right of the main axis46. The index mark 210 can also include a visual or tactile identifier(for example, a raised letter “R” in FIG. 15) to further aid thephysician in ascertaining the orientation.

The fitting 104 can also include additional auxiliary index marks (twoof which 214 and 216 are shown in FIG. 15) and associated visual ortactile identifiers (respectively, “U” and “D”). Alignment of the mark212 with auxiliary mark 214 indicates that the deflection orients thedispensing end 34 upward. Likewise, alignment of the mark 212 withauxiliary mark 216 indicates that the deflection orients the dispensingend 34 downward. Another auxiliary mark and associated identifier (notshown), located diametrically opposite to the mark 210, can alsoindicate a left orientation of the deflected dispensing end 34.

The alignment of the index mark 212 with the index marks 210, 214, and216 allows the physician to remotely orient the deflected end 34 in adesired way, without reliance upon x-ray or other internal visualizationtechnique. Tracking the rotation of the index mark 212 relative to oneor more of the index marks 210, 214, or 216 also allows the physician togauge the rotation of the injection tube 30, to achieve the degree ofrotation necessary to cut the cement bolus 62 loose.

When the dispensing end 34 is steerable (as shown in FIG. 3), alignmentof the marks 210 and 212 can designate that the steering wires 50 and 52extend in a particular vertical or horizontal plane. With thisorientation known, the physician can operate the steering mechanism 56to achieve the desired bending action, without reliance upon x-ray orother form of internal visualization. Relative movement of the indexmarks also allows the physician to monitor the extent of rotation of theinjection tube 30 when cutting the cement bolus 62 loose.

When the dispensing end 34 includes a side dispensing port 180 (as shownin FIGS. 12 and 13), alignment of the marks 210 and 212 can designatethe orientation of the dispensing port 180, either left, right, up, ordown. Relative movement of the index marks also allows the physician tomonitor the extent of rotation of the injection tube 30 when cutting thecement bolus 62 loose.

C. Radiological Monitoring

In all the embodiments shown in FIGS. 2 to 15, the nozzle assembly 10includes one or more radiological markers 68. The markers 68 are madefrom known radiopaque materials, like platinum, gold, calcium, tantalum,and other heavy metals. At least one marker 68 is placed at or near thedispensing end 34, to allow radiologic visualization of the dispensingend 34 within the targeted bone area.

Other forms of markers can be used to allow the physician to visualizethe location of the dispensing end 34 within the targeted treatmentarea.

II. Deployment of Nozzle Assembly in a Vertebral Body

Use of the nozzle assembly 10 will now be described when deployed in ahuman vertebra 150, which FIG. 16 shows in coronal (top) view. It shouldbe appreciated, however, the nozzle assembly 10 is not limited in itsapplication to vertebrae. The system 10 can be deployed equally as wellin long bones and other bone types.

The vertebra 150 includes a vertebral body 152, which extends on theanterior (i.e., front or chest) side of the vertebra 150. The vertebralbody 152 includes an exterior formed from compact cortical bone 158. Thecortical bone 158 encloses an interior volume of reticulated cancellous,or spongy, bone 160 (also called medullary bone or trabecular bone).

The vertebral body 152 is in the shape of an oval disk, which isgenerally symmetric about an anterior-posterior axis 154 and amid-lateral axis 156. The axes 154 and 156 intersect in the middleregion or geometric center of the body 152, which is designated MR inthe drawings.

As FIG. 16 shows, access to the interior volume of the vertebral body152 can be achieved. e.g., by drilling an access portal 162 through aside of the vertebral body 152, which is called a postero-lateralapproach. The portal 162 for the postero-lateral approach enters at aposterior side of the body 152 and extends at angle forwardly toward theanterior of the body 152. The portal 162 can be performed either with aclosed, minimally invasive procedure or with an open procedure.

As FIG. 16 shows, a guide sheath 166 is located in the access portal162. Under radiologic, CT, or MRI monitoring, the tool 12 is introducedthrough the guide sheath 166, with the expandable body 20 collapsed.When deployed in the cancellous bone 160, the physician conveys apressurized fluid into the body 20 to expand it. The fluid is preferablyradio-opaque to facilitate visualization. For example, Renografin™contract media can be used for this purpose.

Expansion of the body 20 within the interior volume compressescancellous bone 160 to form a cavity 164. The compaction of cancellousbone also exerts interior force upon cortical bone 158, making itpossible to elevate or push broken and compressed bone back to or nearits original prefracture position.

The body 20 is preferably left inflated for an appropriate waitingperiod, for example, three to five minutes, to allow coagulation insidethe vertebral body 152. After the appropriate waiting period, thephysician collapses the body 20 and removes it. As FIG. 17 shows, theformed cavity 164 remains in the interior volume of the vertebral body152.

As FIG. 17 shows, the second tool 14 is now readied for deployment. Withthe cartridge 26 filled with cement 38, the physician directs theinjection tube 30 through the guide sheath 166 into the formed cavity164.

If the dispensing end 34 is normally biased into a bent condition (asexemplified in FIG. 2), passage through the guide sheath 166 overcomesthe bias and straightens out the dispensing end 34. Once free of theguide sheath 166, the dispensing end 34 returns to its normally biasedcondition.

As shown in FIGS. 19A, 19B, and 19C, the tube 30 can includeprepositioned markers 218(0) to 218(2) along its length. The markers218(0) to 218(2) are positioned to successively align with the proximaledge 220 of the guide sheath 166 at intervals that mark the extent towhich the dispensing end 34 extends beyond the distal edge 222 of theguide sheath 166.

As FIG. 19A shows, when marker 218(0) and the proximal edge 220 align,the distal edge 222 of the guide sheath 166 and the dispensing end 34are coincident (i.e., the tip of the dispensing end 34 coterminous withthe distal edge 222 of the sheath 166).

As FIG. 19B shows, subsequent movement of the tube 30 in the sheath 166brings the marker 218(1) into alignment with the proximal edge 220. Thisalignment indicates that the tip of the dispensing end 34 projectsbeyond the distal edge 222 by a first, predetermined distance D1.

As FIG. 19C shows, subsequent movement of the tube 30 to further advancethe dispensing end 34 brings the marker 218(2) into alignment with theproximal edge 220. This alignment indicates that the dispensing end 34projects beyond the distal edge 222 by a second, predetermined distanceD2.

Of course, the number and spacing of the markers 218 can vary. Themarkers 218 allow the physician to gauge when and to what extent thedispensing end 34 projects into the targeted site, without need fordirect visualization.

Under radiologic visualization provided by the markers 68, the physicianmay rotate the injection tube 30. Rotation of the injection tube 30orients the dispensing end 34 within the cavity 164 before or during theinjection of cement 38. In the embodiment shown in FIG. 14, the rotationmay be accomplished without rotating the gun 22. In the embodiment shownin FIG. 15, the extent of rotation and the orientation of the dispensingend 34 can be observed using the markers 212/210, 214, and 216 on thefitting 104 (see FIG. 15), without active internal visualization.

Alternatively, if the tube 30 carries one or more steering wires 50 and52 (as exemplified in FIG. 3), the physician may selectively bend thedispensing end 34 under radiological visualization provided by themarkers 68. In this way, the physician can steer the dispensing end 34into the desired position or positions within the cavity 164 before orduring injection of cement 38. In the embodiment shown in FIG. 15, themarkers 212/210, 214, and 216 on the fitting 104 aid the steeringprocess (see FIG. 15), without active internal visualization.

As shown in FIG. 17, the postero-lateral access portal 162 does notalign the injection tube 30 with the geometric axes 154 and 156 of thevertebral body 152. Nevertheless, deflection of the dispensing end 34aligns the end 34 in the middle region MR of the body 152 along themid-lateral axis 156.

As FIG. 17 shows, the gun 22 urges the cement 38, or other fillingmaterial, into the cavity 164. While injecting the material 38, thephysician preferably begins with the dispensing end 34 positioned in thelateral region opposite to the access portal 162. As the material 38flows into the cavity 164, the physician progressively moves thedispensing end 34 along the mid-lateral axis 156 through the middleregion MR and toward the access portal 162. The deflection of thedispensing end 34 (by virtue of either the preformed bias or by activesteering) allows the physician to maintain the desired alignment withthe mid-lateral axis 156. The deflection of the dispensing end 34 (byvirtue of either the preformed bias or by active steering) also allowsthe physician to keep the dispensing end 34 continuously submerged inthe filling material 38, to thereby avoid the formation of air or fluidpockets.

The physician observes the progress of the injection radiologicallyusing the markers 68, positioning the dispensing end 34 by rotation orsteering, or both, as just described.

The physician flows material 38 into the cavity 164, until the material38 reaches the interior end of the guide sheath 166. If the dispensingend 34 carries one or more exterior loops (as exemplified in FIGS. 4 to10), or a side dispensing port 180 (as exemplified in FIGS. 12 and 13),rotation of the dispensing end 34 will cleanly sever the injected cementbolus residing in the cavity 164 from the unexpelled cement residingwithin the dispensing end 34 (as FIGS. 4 and 5 and FIGS. 12 and 13show). In this way, cement residing in the cavity 164 will not beinadvertently drawn out of the cavity 164 upon withdrawal of thedispensing end 34. Rotation of the dispensing end 34 to sever thematerial bolus also avoids the formation of sharp pedicles in thematerial bolus, which could irritate surrounding tissue.

In the embodiment shown in FIG. 15, the markers 212/210, 214, and 216 onthe fitting 104 aid in monitoring the extent of rotation, without activeinternal visualization.

As FIG. 18 shows in a lateral view, access into the interior volume of avertebral body 152 can also be accomplished by drilling an access portal168 through either pedicle 170. This is called a transpedicularapproach. As FIG. 18 shows, the access portal 170 for a transpedicularapproach enters at the top of the vertebral body 152, where the pedicle170 is relatively thin, and extends at an angle downward toward thebottom of the vertebral body 152 to enter the interior volume.

The tool 12 is deployed through a guide sheath 166 in the portal 168 toform a cavity 172, in the same manner described above. The physician canmanipulate the second tool 14 to steer the dispensing end 34 of thenozzle assembly 10 into the cavity 172. Although the transpedicularaccess portal aligns the tube 30 obliquely with respect to the axes 154and 156, the deflected dispensing end 34 can be rotated into generalalignment with either the anterior-posterior axis 154 or the mid-lateralaxis 156 while injecting cement.

The deflected dispensing end 34 allows the introduction of cement 38into the middle region MR of the vertebral body 152, using eitherpostero-lateral access or a transpedicular access. The cement 28, whenhardened, provides support uniformly across the middle region MR. Thecapability of the vertebral body 152 to withstand loads is therebyenhanced.

The above described procedure, carried out in a minimally invasivemanner, can also be carried out using an open surgical procedure. Usingopen surgery, the physician can approach the bone to be treated as ifthe procedure is percutaneous, except that there is no skin and othertissues between the surgeon and the bone being treated. This keeps thecortical bone as intact as possible, and can provide more freedom inaccessing the interior volume of the vertebral body 152.

III. Cooled Nozzle Assembly

After mixing and while curing, the cement 38 undergoes a chemicalreaction that generates heat. When the cement temperature is below agiven threshold value, the cement 38 maintains a flowing, viscous liquidstate, which is suited for introduction through the nozzle assembly 10into the targeted region. As the temperature increases beyond thethreshold value, the cement 38 begins to harden, progressively losingits flow characteristic and becoming more resistant to passage throughthe nozzle assembly 10. It is desirable to expel the loose cement bolus62 before the threshold temperature is reached.

FIG. 20 shows a system 240 for cooling the nozzle assembly 10 duringpassage of the cement 38 through the dispensing end 34. The system 240includes the injection tube 30, which is releasably coupled to the frontend of the cartridge 26 by the threaded connector 36, as previouslydescribed. The tube 30 includes the center lumen 30, through whichcement 38 conveyed from the cartridge 26 passes.

The system 240 further includes at least one paired set of side lumens,which extend through the tube 30 axially beside the center lumen 30. Inthe illustrated embodiment (see FIG. 22), four paired lumen sets areshown, designated 242 A and B, 244 A and B, 246 A and B, and 248 A andB. As shown in FIGS. 21 and 22, each lumen set 242A/B; 244A/B; 246A/B;and 248A/B comprises a closed loop for carrying a cooling fluid from asource 250, through the tube 30, and to waste 252.

As best shown in FIG. 21, the lumen designated A in each set 242A/B;244A/B; 246A/B; and 248A/B communicates at its proximal end with thecooling fluid source 250 via an in line pump 254. The lumen designated Ain each set 242A/B; 244A/B; 246A/B; and 248A/B therefore comprises aninlet path for the cooling fluid.

As FIG. 21 also shows, the inlet lumen A of each set 242A/B; 244A/B;246A/B; and 248A/B communicates at its distal end with the distal end ofthe lumen designated B in its respective set 242A/B; 244A/B; 246A/B; or248A/B. As FIGS. 21 and 22 show, communication between the distal endsof the lumens A and B in each set 242A/B; 244A/B; 246A/B; and 248A/B isestablished by removing material between the lumens A and B to form achannel 256 between them, and laying a sealing material 258 over thechannel 256. The proximal ends of the lumens B in each set 242A/B;244A/B; 246A/B; and 248A/B communicate with waste 252. The lumen B ofeach set 242A/B; 244A/B; 246A/B; and 248A/B thereby comprises a returnpath for the cooling fluid.

At the source 250, the cooling fluid is at a desired temperature, whichis cooler than the threshold temperature of the cement 38. For example,the source fluid can comprise tap water at a temperature of about 68° F.(20° C.). While cement 38 is conveyed by the center lumen 32 fordischarge, the pump 254 conveys cooling fluid from the source 250through the inlet paths 242A, 244A, 246B, and 248B. The return paths242B, 244B, 246B, and 248B carry the cooling fluid to waste 252. Thecirculation of cooling fluid in the tube 30 along the center lumen 32dissipates heat generated by the curing cement 38, to mediate thetemperature increase in the curing cement 38. The circulation of coolingfluid thereby keeps the curing cement 38 in the center lumen 32 in aviscous flowing condition for a longer period of time.

In the illustrated embodiment (see FIGS. 20 and 21), the return paths242B, 244B, 246B, and 248B convey cooling fluid to waste 252 downstreamof proximal end of the center lumen 30. This quickens the discharge ofheated return fluid from the tube 30 to thereby further minimize thetemperature increase within the center lumen 32.

It should be appreciated that the system 250 can also include a cuttingelement to sever the cement flow in response to rotation of the tube 30,as well as means for deflecting the dispensing end 34, in any of themanners previously described.

IV. Injector Nozzle Assembly With Variable Delivery Rates

FIGS. 23 to 25 show another embodiment of an injector nozzle assembly300 for conveying a flowable material 302 into bone or another location,such as a cavity, in the body. Like the injector nozzle assembliespreviously described, the assembly 300 shown in FIGS. 23 to 25 iscapable of carrying diverse types of flowable materials, e.g., bonecement or a suspension of one or more therapeutic substances, or both atthe same time. The assembly 300 shown in FIGS. 23 and 24 can likewise beused for diverse therapeutic purposes, as well, e.g., to treat adiseased bone, or to prevent or treat fracture or collapse of a bone, orboth at the same time.

As shown in FIGS. 23 to 25, the assembly 300 comprises a syringe body304 coupled to a syringe handle 306. In use, a volume of flowablematerial 302 is loaded into the syringe body 304(see FIGS. 26 and 27).As FIG. 24 best shows, a syringe plunger 308 is carried in a plungerchamber 310 formed in the interior of the syringe handle 306. Thesyringe plunger 308 axially advances through the syringe body 304,thereby expelling the flowable material 302 out the distal end of thesyringe body 304 (as FIGS. 26 and 27 show).

The syringe handle 306 and syringe body 304 can comprise, e.g., formedplastic or metal parts. The syringe handle 306 can be formed to possessdifferent shapes and sizes. It is desired that the handle 306 is sizedto fit comfortably in the hand of an operator.

The syringe body 304 can comprise a component that can be easily coupledto the handle 306 at time of use and then decoupled from the handle 306and discarded after use. An o-ring 334 (see FIG. 25) desirably seals theperiphery of the releasable junction between the body 304 and the handle306. Syringe bodies 304 possessing different lengths and/or differentinterior volumes can also be provided, to meet the particular deliveryobjectives of the targeted site. The syringe plunger 308 desirablycomprises a material, e.g., polyisoprene rubber, that makes movingsealing engagement against the interior wall of the syringe body 304, toexert an expelling force upon the material 302.

A plunger advancement mechanism 312 is carried by the syringe handle306, as FIGS. 23 and 24 best show. The mechanism 312 is coupled to thesyringe plunger 308. As FIGS. 26 and 27 show, force applied to theplunger advancement mechanism 312 causes the syringe plunger 308 to moveaxially through the plunger chamber 310 and the syringe body 304,thereby expelling the flowable material from the body 304.

Desirably, the plunger advancement mechanism 312 is configured toaccommodate different delivery objectives. For example, in a firstdelivery mode, the advancement mechanism 312 causes the syringe plunger308 to advance or retract a set distance per rotation of a firstactuator 314. In a second delivery mode, the advancement mechanism 312causes the syringe plunger 308 to advance or retract at a different setdistance per rotation of a second actuator 316.

In the illustrated embodiment, the first axial displacement is greaterthan the second axial displacement. The operator is thereby able toexpel material 302 from the syringe body 304 in the first delivery modemore quickly per rotation of the actuator than in the second deliverymode. The operator can thereby easily switch from a relatively rapid,high volume discharge of flowable material, when so desired, torelatively slower, more metered, lower volume discharge of flowablematerial, when so desired. The operator is also able, in the first, highvolume delivery mode, to rapidly retract the syringe plunger 308, towithdraw the pressure force of the syringe plunger 308 against thematerial 302, to thereby quickly terminate the flow of material from thesyringe body 304. The ability to start and stop both large volume flowand metered, smaller volume flow makes it possible to rapidly respond toin situ flow conditions, to thereby prevent or minimize the flow ofmaterial 302 under pressure through cracks, openings, or voids incortical bone, in a process called “extravazation.” The operation of theplunger advancement mechanism 312 to achieve a variable rate of deliverycan be implemented in various ways. In the illustrated embodiment, theplunger advancement mechanism 312 responds to the application ofrotational force to advance the syringe plunger 308. In thisarrangement, rotatable first and second actuators or control knobs 314and 316 are carried at the proximal end of the syringe handle 306. Inuse, the operator holds the syringe handle 306 in one hand, whileapplying force with the other hand to rotate either the first or secondcontrol knob 314 and 316. As FIG. 26 shows, rotation of the firstcontrol knob 314 advances the syringe plunger 308 at a first axialdisplacement per rotation, to discharge a given volume of material 302per amount of rotation. As FIG. 27 shows, rotation of the second controlknob 316 advances the syringe plunger 308 at a slower, second axialdisplacement per rotation, discharging a lesser volume of material 302per amount of rotation.

In the illustrated embodiment (see FIG. 25), the syringe plunger 308 isattached to the distal end of a threaded slow advancement screw 318. Inthe illustrated embodiment, a snap fit clip 332 is provided on thedistal end of the slow advancement screw to couple the plunger 308 tothe screw 318. The second rotatable control knob 316 is attached to theopposite end of the slow advancement screw 318, to rotate the slowadvancement screw 318 about its axis.

The threaded slow advancement screw 318 is itself carried within thebore 322 of an externally threaded fast advancement screw 320. Theexterior threads 324 of the slow advancement screw 318 engage interiorthreads 326 in the bore 322 of the fast advancement screw 320 (see FIG.25). Rotation of the slow advancement screw 318 about its axis causesthe slow advancement screw 318 to move relative to the fast advancementscrew 320, either fore or aft, depending upon the direction of rotation.The syringe plunger 308 carried at the end of the screw 318 is therebyalso caused to move.

The fast advancement screw 320 is itself coupled to the first controlknob 314, which is rotatably coupled to the syringe handle 306. Thefirst control handle 314 includes an annular, internally threadedaperture 328 (see FIG. 25). The threaded aperture 328 engages theexternal threads 330 of the fast advancement screw 320. As FIG. 23shows, when the fast advancement screw 320 is threadably engaged in thefirst control knob 314, the slow advancement screw 318, which is itselfthreaded in the fast advancement screw 320, extends into the handle 306.The syringe plunger 308, carried at the distal end of the slowadvancement screw 318, extends into the plunger chamber 310. Rotation ofthe first control knob 314 about the fast advancement screw 320 movesthe fast advancement screw 320 fore or aft, depending upon the directionof rotation. The slow advancement screw 318 moves in tandem with thefast advancement screw 320, causing the syringe plunger 308 to also movein the plunger chamber 310 and syringe body 304 in response to rotationof the first control knob 314. As before explained, rotation of thesecond control knob 316 will likewise independently cause movement ofthe slow advancement screw 318 within the fast advancement screw 320,likewise moving the syringe plunger 308 within the plunger chamber 310and syringe body 304. The distance and direction that the syringeplunger 308 travels in one rotation of either the slow advancement screw318 or the fast advancement screw 320 is controlled by the configurationof the mating threads.

In a representative embodiment, the exterior threads 324 of the slowadvancement screw 318 comprise 10-degree modified right handed squarethreads (class 2G, single start), with sixteen threads to the inch. Inthis arrangement (see FIG. 27), clockwise rotation of the slowadvancement screw 318 advances the syringe plunger 308 toward the distalend of the syringe body 304, and counter-clockwise rotation of the slowadvancement screw 318 retracts the syringe plunger 308 away from thedistal end of the syringe body 304. One revolution of the second controlknob 316 moves the syringe plunger 308 about one-sixteenth ( 1/16th) ofan inch.

Likewise, in a representative embodiment, the exterior threads 326 ofthe fast advancement screw 320 comprise 10-degree modified left handedsquare threads (class 2G, three start), with six threads to the inch. Inthis arrangement (see FIG. 26), counter-clockwise rotation of the fastadvancement screw 320 retracts the syringe plunger 308 away from thedistal end of the syringe body 304, and clockwise rotation of the fastadvancement screw 320 advances the syringe plunger 308 toward the distalend of the syringe body 304. One revolution of the first control knob314 moves the syringe plunger 308 about one-half (½) inch. Thus, asingle rotation of the first control knob 314 moves the syringe plunger308 farther than a single rotation of the second control knob 316,expelling a greater volume of material 302 per rotation of the actuator.

As described, the plunger advancement mechanism 312 is operatedmanually. It should be appreciated that the plunger advancementmechanism can be operated by means of an electric motor or the like.

The assembly 300 shown in FIGS. 23 to 27 can be used to convey material310 into a cavity created in cancellous bone by an expandable structure,as earlier described and as shown in FIGS. 16 and 17. The assembly 300may also be used in association with a vertebroplasty procedure, whichinjects cement under pressure into a vertebral body, without priorformation of a cavity.

In a representative embodiment, the syringe handle 306 (which can bemade of polycarbonate) measures about 3.9 inches in length and 2.6inches in width. The syringe body 304 (which also can be made ofpolycarbonate) measures about 5.1 inches in overall length, with aninterior lumen having an inside diameter of about 0.5 inch.

In this representative embodiment, the first control knob 314 (which canbe made from Celcon™ plastic material) is shaped round and has adiameter of about 2.5 inches. The fast advancement screw 320 (which canalso be made from Celcon™ plastic material) has a length of about 4.5inches and an outside thread diameter of about 0.75 inch. The internalthreads extend for a distance of about 0.75 inch.

In this representative embodiment, the slow advancement screw 318 (whichcan also be made from Celcon™ plastic material) extends from the secondcontrol knob 316 for a length of about 9.35 inches and has an outsidethread diameter of about ⅜ inch. The second control knob 316 iselliptical in shape, measuring about 2.0 inches along its major axis,about 0.625 inch along its minor axis, and about 1.5 inches in height.

The features and advantages of the invention are set forth in thefollowing claims.

1. A method comprising selecting a vertebral body for treatment having acortical wall enclosing a cancellous bone volume, establishing apercutaneous access having a longitudinal axis leading to the cancellousbone volume, introducing a device into the vertebral body through thepercutaneous access path, the device defining a deflected path along adeflected axis angled with respect to the longitudinal axis,manipulating the device to modify the cancellous bone volume forintroduction of bone filling material, and introducing bone fillingmaterial into the cancellous bone volume modified by the deviceincluding introducing bone filling material along the percutaneous pathand along the deflected path, and directing discharge of the bonefilling material into the cancellous bone volume through an opening thatis oriented at an angle relative to the deflected axis.
 2. A methodaccording to claim 1 wherein the percutaneous path comprises atranspedicular path.
 3. A method according to claim 1 wherein thepercutaneous path comprises a postero-lateral path.
 4. A methodaccording to claim 1 wherein the percutaneous path is established, atleast in part, by a cannula.
 5. A method according to claim 4 whereinintroducing bone filling material into the cancellous bone volumeincludes withdrawing the cannula along the longitudinal axis whiledirecting discharge of the bone filling material through the dischargeopening.
 6. A method according to claim 1 wherein the discharge-openingis oriented at generally a right angle relative to the deflected axis.7. A method according to claim 1 wherein the opening comprises a sidedischarge port.
 8. A method according to claim 1 wherein directingdischarge of the bone filling material into the cancellous bone volumeincludes altering the orientation of the opening.
 9. A method accordingto claim 1 wherein modifying the cancellous bone volume includescontacting cancellous bone with the device.
 10. A method according toclaim 1 wherein modifying the cancellous bone volume includes expandingthe device for contact with cancellous bone.
 11. A method according toclaim 1 wherein modifying the cancellous bone volume includes inflatingthe device for contact with cancellous bone.
 12. A method according toclaim 1 wherein modifying the cancellous bone volume includesmanipulating the device to create a cavity in cancellous bone.
 13. Amethod according to claim 1 wherein modifying the cancellous bone volumeincludes manipulating the device to move fractured cortical bone.
 14. Amethod according to claim 1 wherein the bone filling material comprisesbone cement.
 15. A method according to claim 1 wherein introducing bonefilling material into the cancellous bone volume includes coupling adelivery tube to an injector of bone filling material, advancing thedelivery tube along the percutaneous path, and operating the injector toconvey bone filling material along the percutaneous path through thedelivery tube.
 16. A method according to claim 15 wherein the deliverytube includes a threaded coupling for coupling the delivery tube to theinjector.